1. Field of the Invention
The present invention relates to a gas sensor including a gas sensor element that detects the concentration of a gas to be measured.
2. Description of the Related Art
A gas sensor is attached to an intake air system (for example, an intake air pipe or an intake air manifold) of an internal combustion engine such as a diesel engine, a gasoline engine or the like, and a specific gas concentration is monitored so that the combustion state or the like is controlled. A structure of such a gas sensor is described in Patent Document 1. However, in the gas sensor that is attached to the intake air system of the internal combustion engine, since the attachment is restricted by a structure or a layout in a vicinity of the intake air pipe, an axis of the gas sensor itself is inclined and attached to an axis of the intake air pipe. The gas sensor is fixed to the intake air pipe such that a male threaded section provided at the outside of a case (a metal shell) accommodating the gas detection element therein is tightened into a female threaded section that is incorporated into a wall surface of the intake air pipe.
When a vehicle having mounted therein the internal combustion engine is subjected to impact, secure clearance between the hood and the engine components is required for improving safety. In this regard, there is a need to shorten the projection length of the gas sensor projecting towards the outside of the intake air pipe.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2008-268152-A
3. Problems to be Solved by the Invention
Since the above-described known gas sensor is attached to the intake air pipe using the male threaded section of the case, if the axis of the male threaded section of the case and the axis of the female threaded section of the intake air pipe are inclined, an attachment angle of the gas sensor can be changed with respect to the intake air pipe. However, the depth of attachment of the gas sensor is difficult to change, and the extent to which the projection length that the gas sensor projects towards the outside of the intake air pipe can be shortened is limited.